Learn about projects and solutions using Visual Basic

Applies to: Visual Studio Visual Studio for Mac

In this introductory article, we'll explore what it means to create a solution and a project in Visual Studio. A solution is a container that's used to organize one or more related code projects, for example a class library project and a corresponding test project. We'll look at the properties of a project and some of the files it can contain. We'll also create a reference from one project to another.

We'll construct a solution and project from scratch as an educational exercise to understand the concept of a project. In your general use of Visual Studio, you'll likely use some of the various project templates that Visual Studio offers when you create a new project.

Solutions and projects

Despite its name, a solution is not an "answer". A solution is simply a container used by Visual Studio to organize one or more related projects. When you open a solution in Visual Studio, it automatically loads all the projects that the solution contains.

Create a solution

We'll start our exploration by creating an empty solution. After you get to know Visual Studio, you probably won't find yourself creating empty solutions often. When you create a new project, Visual Studio automatically creates a solution to house the project if there's not a solution already open.

Add a project

Now let's add our first project to the solution. We'll start with an empty project and add the items we need to the project.

Add an item to the project

We have an empty project. Let's add a code file.

1. From the right-click or context menu of the QuickDate project in Solution Explorer, choose Add > New Item.

   The Add New Item dialog box opens.

2. Expand Common Items, then choose Code. In the middle pane, choose the Class item template. Name the class Calendar, and then choose the Add button.

   A file named Calendar.vb is added to the project. The .vb on the end is the file extension that's given to Visual Basic code files. The file appears in the visual project hierarchy in Solution Explorer, and its contents open in the editor.

3. Replace the contents of the Calendar.vb file with the following code:

   Class Calendar
       Public Shared Function GetCurrentDate() As Date
           Return DateTime.Now.Date
       End Function
   End Class
   

   The Calendar class contains a single function, GetCurrentDate, that returns the current date.

4. Open the project properties by double-clicking My Project in Solution Explorer. On the Application tab, change Application type to Class Library. This step is necessary to build the project successfully.

5. Build the project by right-clicking on QuickDate in Solution Explorer and choosing Build. You should see a successful build message in the Output window.

Add a second project

It's common for solutions to contain more than one project, and often these projects reference each other. Some projects in a solution might be class libraries, some executable applications, and some might be unit test projects or websites.

Let's add a unit test project to our solution. This time we'll start from a project template so we don't have to add an additional code file to the project.

1. From the right-click or context menu of Solution 'QuickSolution' in Solution Explorer, choose Add > New Project.

Add a project reference

We're going to use the new unit test project to test our method in the QuickDate project, so we need to add a reference to that project. The reference creates a build dependency between the two projects, meaning that when you build the solution, QuickDate is built before QuickTest.

Add test code

Project properties

(Optional) Run the test

Next steps

If you want to further explore Visual Studio, consider creating an app by following one of the Visual Basic tutorials.

See also

• Create projects and solutions
• Manage project and solution properties
• Manage references in a project
• Develop code in Visual Studio without projects or solutions
• Visual Studio IDE overview